Engine crankcase construction



March 20, 1945. v

- 2 Sheets-Sheet l Filed Nov. 13, 1942 Srwentor March 20, 1945. w. E. BRILL.

ENGINE CRANKCAS CONSTRUCTION Filed Nov. 15, 1942 42 Sheets-Sheet 2 ,l 9L (Ittornegs Patented 20, 1945 ENGINE cnANKcssE ooNs'rnUc'rioN William Elmer Drill, Cleveland, Ohio, assignor to General Motors Corporation, Detroit, Mich., a

corporation o! Delaware Application November I3, 1942, Serial N o. V465,1!52 l Claims. (Ci. 121-194) i Thepresent invention relatesto internal combustion engines, more especially to a welded crankcase construction for engines' of the multicylinder bank type. l

In enginesof the above* type the cylinders and upper crankcase are usually cast en bloc and transverse webs are provided betweeneach main crankshaft bearing and the cylinders of each bank whose conecting rods are connected to.

the crank throw between each main bearing to '1 prevent deflection of the crankcase in the vertical, horizontal and longitudinal plane of the engine. These castwebsv are of thick section in the longitudinal direction 'and the length of the engine is accordingly increased. In order to decrease the overall length and weight of. the y engine the cylinders of alternate banks are sometimes staggered but the diiiiculties in providing cast webs of suitable form `to properly distribute the load between these staggered cylinders and .29

the main bearings and to provide the necessary clearance therebetween for the crank throws and connectingv rods` does not materially decrease the lengthof the engine or its weight.

The principal object of the present invention is to provide a rigid light weight ,welded crankcase construction for a multi-cylinder engine in which the cylinders are arranged in a plurality of banks and the cylinders in adjacent banks may be greatly staggered to materially reduce the length of the engine and also the weight thereof;

The crankcase construction by which the above object is accomplished will b e better understood by the reference to the following detailed description and drawings illustrating a construction for a light weight, multi-cylinder', compression ignition engine of the two stroke type `hav--` ing 4 banks of cylinders arranged at an angle ior operating a single crankshaftfthe cylindersof adjacent banks being arranged in staggered relation to reduce the length of the engine.

Figure 1 of the drawings is a transverse sectional view of the upper crankcase taken on line IIvofFigure2.

' me 2 15 lonltildinal section taken o'n line v [-12 0f Figllle 1. A

, Figure l3 is a bottom plan view of the upper crankcase as indicated on line S--S of Figure 2. Figure 4 is a perspective view of one of the corrugated webs welded between each main bear- 5 ing andthe upper portion of the crankcase.

Referring to Figures l, 2-and 3 it willbe cbserved that the upper crankcase is-made up of a semi-cylindrical. plate member I having diafnietrically extending :langes 3 and a plurality of longitudinal spaced corrugated web plates I extending .transverselyl with respect to and welded to the inner surface of the member I and nanges 3. The corrugated web plates 5 are of -generally semiannular shape as best shown in` Figure 4. The outer semicircular corrugated edge of each web plate I is welded to the inner cylindrical surface of the member I. andthe up per half of the engine main bearings shown generally at 1 are welded to the central semicircular edge of the web plates B and alsoto the.

vertical edge of the flanges 3 of the member I. The diametral edges of the web plates 5 are also welded to the upper diametrical surface of the flanges 3. The above described light 'weight welded upper crank is thus adequately reinforced against vertical, horizontal, transverse and torque stresses imposed by the forces between the engine cylinders, pistons and -conecting rods not shown, and the crankshaft 9, shown in dash and dot lines in Figures 3,` which is rotatably supported in the main bearings 1.

In order to rigidly nx the cylinder liners, not shown, to the crankcase the following means are employed; the semicylindrical crankcase member I is provided with a plurality of circularl` openings II- arrangedin 4 parallel longitudinal rows, the axis'of the openings in each row extending radially with respect to the center line of the main bearings l[and crankshaft 8, and in each of these openings II a cylinder liner mounting collarV I3 is welded. The openings II in alternaterows are staggered as best shown in Figures' 2 and 3, and four of these openings are Vlocated between adjacent transverse w'eb plates.

Each pair, of each of these fouropenings, lo-

cated in alternate rows and between adjacent web plates 5 are displaced on opposite sides of a vertical transverse plane midway, 4between the mid-plane of the adjacent web plates 5 a distance substantially equal to the one half therme`-V ternal diameter of the cylinder hner collars -I 3. The web members as best shown in Figures 2. 3 and 4 have four corrugations A, B'. C and D extending alternately on both sides of its mid-plane to points half way between the circular openings I I Ain each of the four longitudinal rows. It will be noted that the outer edges of the corrugations A. B, C and D extend transversely with respect tothe member I and are welded to the inner surface thereof. vat points midway between Aeach of the openings II.

are welded at their-apex to the outer surface oi' Transversely extending V shaped members I6. as best shown in Figure 2.-`

the corrugations A, B, C and D of each of the web plates are welded to the inner surface of the member I, and plates I I extending transversely and in the plane of each leg of the V members are welded to each of these legs to act as stools for attaching a forged hollow air box member I9 'to both the plates Il and upper surface of the member I. The air box member is provided with substantially radial side walls 2i which are welded to the outer surface of the member I and a top thin walled portion having four longitudinal extending bosses 23, 2Q, 25 and 26 separated by' depressed portions 2l, 28 and 29 essayer,

and crankshaft bearings eeured to the other edges of said transverse p temembers.

2'. A crankcase for a multicylinder engine coniprising a longitudinal member of arcuate section having a plurality of longitudinall lrows of vcylinder openings, alternate 'rows of `said openings serving as pockets for the engine camshafts, not

shown. The opposite ends of the air boxmember I9 and the semi-cylindrical crankcase member are closedoi by plates welded thereto, one of which 30 is shown in Figure 2. Each of the l bosses 23, 24, 25 and 26 have outer plane surfaces normal to the radial axes of the openings II in each of the rows in the member I and are likewise provided with circular openings 3| extending therethrough in axial alignment with the four rows of circular openings II in the member I. Inwardly extending ange portions 3S on the inner surface of the bosses 23, 24, 25 and 2dimmediately adjacent the openings 3i are provided to which the upper edge of the plates il are Y welded, as best shown in Figures 1 and 2. The above crankcase construction enables insertion si cylinder liners through the aligned circular openings I3 and 3i in the member I and bosses 23, 24, 25 and 26 of the air box member i9 enables the upper portion of the liners and cylinder heads, lnot shown, to be attached directly to the bosses by any well known means so that the forces between the engine cylinders, pistons, connecting rods, and cranks operated thereby are equally distributed through the plates Il and corrugations ABCD of adjacent transverse webs 5 to which the main bearings 'i are welded, even though the cylinder liners are staggered or oiset longitudinally with respect to the main bearing 1 and webs 5. The above rigid, light weight crankcase construction for a multi-cylinder engine enables the connectingrods Voperated by the 'staggered cylinders located between adjacent websl 5 to be connected to one or more crank pins of the crankshaft located between the main bearings, and permits the forces between eachy staggered cylinder and its crank to be distributed equally between adjacent main bearings. The

' above structure likewise enables the length and weight of a two-stroke compression ignition en` gine to be reduced materially and provides an beingstaggered and the axis ofl each opening ex-4 tending radially with 'respect -to said longitudinal member, transverse main bearing web plates haveJ "ing an arcuate outeredge with corrugations therein,the alternate corrugations of said web plates extending either side vof the center plane thereof and secured to the inner surface of said longitudinal member midway between the adiacent openings in each of said staggered rows of openings therein. l v

f 3. A Welded crankcasefor a multicylinder engine comprising a crankcase plate of arcuate section having a plurality of staggered longitudinal rows of cylinder vopenings extendingy radially therethrough, aplurality of transversely extending webs having arcuate outer edges, said webs being spaced longitudinally with respect to saidplate, main bearings welded to the central portion of each said webs, each of said webs being corrugated at the outer arcuate edge and the alternate corrugations therein, extending an equal distance either side of the central plane thereof and welded to the internal arcuate surface of said plate midway between adjacent cylinders opening in each of the staggered rows of 'openings in said crankcase plate.

4. A welded crankcase yfor a multicylinder engine comprising ay crankcase plate of arcuate ses tion having a plurality of staggered longitudinal rows of cylinder openings Aextending radially therethrough, a plurality of web plates spaced longitudinally with respect to said outer member, said web plates extending transversely with re-l spect to said member and having an outer arca5 ate edge portion having corrugations welded to the inner surface of said outer member. the alter-z nate corrugations of said web plates extending longitudinally an equal 'distance either side oi the center transverseplane thereof, each of said alter nate oorrugatlons being welded to points in said arcuate member equi-distant between-adjacent openings therein `in each of said staggered rows `air box superstructure to be rigidly welded thereto for supporting the cylinder liners and the central portion of the web members not beingI corrugated allows the accessibility to the main bearing bolts and nuts and provides ample cleanance for the crankthrows of the crankshaft rotatable on either side of the webs.

` I claim: V 1. A crankcase for a multicyllnder engine com prising a longitudinal plate member having apiu rality or longitudinal rows of openings for engine x cylinders, the openings in alternate rows being staggered, a plurality `of transverse plate mem bers having alternate corrugations' at one edge thereof, said corrugations extending angularly outward from the mid-plane of the other edge ci the transverse members, said alternate corrugationsl being secured to said-longitudinal plate member midway between adjacent openings. in

each of said staggered rowsoi' openings therein,

of openings.' d Y 5. Av welded crankcase for a multicylinder engine having alongitudinal member of arcuate section having a plurality er longitudinal rows of cylinder liner openings, the opelfii'ngs in alter nate rows being longitudinally staggered and each opening extendingradially through said arcuate member, a hollow member welded tothe outer arcuate surface of said longitudinal member having a plurality of longitudinally extending cylinder liner support bosses, each of said bosses hav ing cylinder liner openings in radial alignment with the openings in said longitudinal member and inwardly extending flanges adjacent said openings in each. of said bosses, a. plurality of transverse web members spaced longitudinally within said longitudinal member, each of lsaid web mem bers having an arcuate outer edge having corrieY gations therein which are welded to the inner surface oi said arcuate member, the alternate cortions extending in equal and opposite direcwelded to points midway between the openings in each longitudinal row of openings in said longitudinal member, plate members welded between s ons from the mid-plane oi the yweb members and t corrugations of said web members are welded, and .the adjacent iianges of said hollow member, and

i gitudinaily spaced with respect to said member, each of said webs having a corrugated arcuate outer edge portion, main bearings secured to the central portion of said webs, the corrugations of each of said webs extending longitudinally either side of the mid-plane of the central p0rtion of said webs and secured to the inner arcuate surface of said crankcase member, a. hollow cylinder liner support member secured to the outer arcuate surface vof lsaid crankcase member. said cylinder liner support member and said crankcase member having aligned openings therein extending radially with respect to the arcuate surface of the latter, the axis ofeach paix' of said aligned openings being located longitudinally midway between the alternate corrugations of adjacent webs, and transverse plates secured to the upper arcuate surface of said craniccase member opposite that where said alternate corrugations of said webs are secured and also member, a plurality of longitudinally spaced secured to points immediately adjacent the open' ings in thevcylinder liner support member.

'7. A welded crankcase for a multicylinder engine comprising an arcuate shaped crankcase transverse bearing supporting webs of semian nular form having corrugations in the outer arcuate edges welded to the inner arcuate surface of said crankcase member, the alternate corrugations of said webs extending longitudinally either side of the mid-plane of the central portions of said webs, a crankshaft main bearing welded to the central portion of each of said webs, said arcuate crankcase member having a plurality of staggered circular openings extending transversely between adjacent webs, the axis of each opening extending radially with respect to said arcuate crankcase member and equidistant between adjacent alternate corrugations of adjacent webs, a hollow airbox welded to the outer arcuate surface of said crankcase outer member having circularopenings in radial alignment with said openings in said crankcase `member and plates welded transversely between'the openings in said air box to points in the'outer surface of said crankcase member directlyv opposite the points where the alternate corrugations of said web members are welded.

WIILIAM ELMER BRILL. 

